, after what was regarded as a poor performance during last week's debate with governor mitt romney. during one fund-raiser last night, the bill graham civic auditorium in san francisco, the president called on his backers to be honest obsessive over the next 28 days, asking them to knock on doors and call on friends and battleground states, and for anyone who questions his drive and dedication, after seeing him debate, he assured the crowd that he very much intends to win this election. he also attacked his opponents' own performance during last week's debate. >> a few nights ago, suddenly, a guy pretending to be mitt romney stood on a stage next to me and said he's changing his plan. he's just going to pretend it doesn't exist. what $5 trillion tax cut? i don't know anything about a $5 trillion tax cut. don't pay any attention to that tax cut behind the curtain. >> reporter: a new pew research center poll shows that among likely voters, governor romney holds a four-point edge over president obama, 49 to 45%. governor romney is also even with the president among registered voters. t